System and method for storing energy, and for recovering stored energy by using liquid and gas as pistons

1. An energy storage system that uses liquid pistons and gas, comprising: a) one or more liquid-gas tanks, within each of which a portion of gas and a stream of liquid are receivable, the stream of liquid functioning as a piston for compressing the received portion of gas, b) one or more electrically powered liquid pumps, for delivering the stream of liquid into each of said liquid-gas tranks; c) one or more compresed gas storage tanks within each of which the compressed gas received from said one or more liquid-gas tanks is storable, d) piping components, branches thereof, and a plurality of control valves by which liquid and gas is controllably deliverable through said storage system; and e) one or more controller in data communication with said plurality of control valves, for managing flow of gas and liquid through said storage system, wherein the one or more controllers are operable to synchronize opening and closing of the plurality of control valves so the cyclical flow of liquid to and from said one or more liquid-gas tanks is always in a same direction and that the compressed gas is prevented from being mixed with the liquid during the cyclical flow, wherein the stored compressed gas is dischargeable externally to said storage system to release the stored energy.

2. The system according to claim 1, wherein each of the injection pipes penetrates the corresponding liquid-gas tanks from a top end, and extends towards thess a bottom end thereof.

3. The system according to claim 1, wherein each of the injection pipes is configured with a predetermined section area relative to the section area of said one or more liquid-gas tanks that defines induced pressure of the liquid therein.

4. The system according to claimed 1, further comprising a power generation system to which to stored compressed gas is dischargeable, said power generation system comprising: i. one or more additional liquid-gas tanks, adapted to intake a portion of compressed gas and to utilize said portion of compressed gas as a piston, for forcing a streaming of liquid through one or more liquid turbines; ii. the one or more liquid turbines, adapted to receive liquid streamd from said one or more additional liquid-gas tanks, thereby to rotate an electric generator for producing electric power; and iii. additional piping components, branches thereof, and a plurality of additional control valves, for enanbling controlled streaming of liquid and gas through said power generation system; wherein the one or more controllers are operable to synchronize opening and closing of the plurality of additional control valves to ensure sufficient flow of gas and liquid through said power generation system to produce electric power.

5. The system according to claim 4, comprising two or more turbines, each of which being effective in a different liquid pressure range.

6. The system according to claim 5, wherein the one or more turbines are selected from the group consisting of: a Pelton turbine, a Francis turbine, or any combination thereof.

7. The system according to claim 4, being adapt configured to refill said one or more additional liquid-gas tanks with liquid returning from the one or more liquid turbines against atmospheric pressure.

8. The system according to claim 4, further comprising a plurality of sensors in data communication with the one or more controllers, adapted to provide information related to liquid and gas in said power generation system.

9. The system according to claim 1, wherein a first of the piping components is a delivery pipe extending from a discharge of said one or more electrically powered liquid pumps, a second of the piping components is a return pipe extending to an inlet of each of said one or more electrically powered liquid pumps, a third of the piping components is a discharge pipe extending from an outlet of a corresponding liquid-gas tank to the return pipe and in communication therewith, and a fourth of the piping components is an injection pipe branching from the delivery pipe and extending within an interior of a corresponding liquid-gas tank, through which the stream of liquid is injected into the corresponding liquid-gas tank, wherein a fifth of the piping components is a transfer pipe in fluid communication with each of said liquid-gas tanks and compressed gas storage tanks, a sixth of the piping components is a branched pipe extending from a port of a corresponding liquid-gas tank or of a corresponding compressed gas storage tanks to the transfer pipe and in communication therewith, and a seventh of the piping components is a gas supply pipe in fluid communication with the transfer pipe, wherein a first of the control valves is operatively connected to each of the injection pipes, a second of the control valves is operatively connected to each of the discharge pipes, a third of the control valves is operatively connected to each of the branched pipes extending from a port of a corresponding liquid-gas tank, a fourth of the control valves is operatively connected to the gas supply pipe, a fifth of the control valves is operatively connected to the transfer pipe between the gas supply pipe and the one or more liquid-gas tanks, and a sixth of the control valves is operatively connected to the transfer pipe between the gas supply pipe and the one or more compressed gas storage tanks, wherein the one or more controllers are operable to synchronize opening and closing of the first, second and third control valves so that the flow of liquid through the delivery pipe, injection pipe, discharge pipe and return pipe is always in a same direction and that the compressed gas is prevented from being mixed with the liquid within the return pipe.

10. The system according to claim 1, further comprising a plurality of sensors in data communication with the one or more controllers, adapted to provide information related to liquid and gas in said storage system.